Gas-drying apparatus



March 2, 1965 J. E. RONEY ETAL GAS-DRYING APPARATUS Filed Sept. 2o, 1961 INVENTQRS JOHN E. RO/VEY WALL/4M c. STUCK .477! ALEXA/V054? C. MCI IVES I" fin-awn; MAL-w; I

United States Patent 3,171,726 GAS-DRYHNG APPARATUS John E. Roney, Monroevilie, William C. Stnekrath, Pittsburgh, and Alexander C. Mclnnes, Export, The, assignors to Mine Safety Appliances Company, Pittsburgh,

Pa, a corporation of Pennsylvania Filed Sept. 26, 1961, Ser. No. 139,544 7 Claims. (Ci. 55-275) This invention relates to apparatus for drying a stream of gas flowing through it, and more particularly to apparatus that will indicate when the drying material is about spent.

As is well known, there are situations where it is desirable to use a drying gas. For example, the water vapor must be removed from air samples delivered to carbon monoxide detector cells that utilize hopcalite. The hopcalite acts as a catalyst to cause carbon monoxide to combine with oxygen to form carbon dioxide. The heat of that reaction is a measure of the amount of carbon monoxide in the sample. However, if there is water vapor in the sample, the catalytic activity of the hopcalite will be inhibited.

It is among the objects of this invention to provide gas drying apparatus, which includes an indicator that will show when the drying material is becoming so saturated with water vapor as to become unsuitable for its purpose, which will continue to remove water vapor for a predetermined time after the indicator has shown the unsuitable condition of the material, which includes a canister that can be quickly inserted in and removed from a receptacle, and in which the passages through the apparatus are formed by the act of inserting the canister in the receptacle.

In accordance with this invention a canister is removable disposed in a receptacle having a base at one end and a removable cover at the opposite end. The base has an axial socket that opens into the receptacle, and an outlet passage connecting the outer end of the socket with the outside of the base beside it. The base also has an inlet passage connecting the outside of the base with the inside of the receptacle beside thes socket. The canister is formed from concentric inner and outer cylinders. There is a cap on the outer end of the outer cylinder adjacent the cover, and a closure for the opposite end of the outer cylinder. The closure is provided with a central opening and with an inlet hole between the cylinders. Preferably, a nipple extends from the central opening into the socket and communicates with the outlet passage. The opposite end of the inner cylinder has an opening therein connecting it with the inside of the outer cylinder. Between the closure and base and in en gagement therewith, there is an annular sealing gasket that is provided with a passage connecting the inlet passage with the inlet hole in the closure. To indicate the condition of the gas-drying material with which the two cylinders are filled, the canister contains a material that changes color when it absorbs a suflicient amount of moisture from the gas flowing through the canister. This material is located adjacent the cap on the outer cylinder and can be checked through a window in the cap.

The preferred embodiment of the invention is illustrated in the accompanying drawing, in which the single figure is a combination side view and vertical section through our apparatus.

Referring to the drawing, a case 1 contains a partition 2 that supports a tubular receptacle R. The body of the receptacle is formed from a sleeve 3 suspended from around a large threaded opening. A removable 3,111,725 Fatented Mar. 2, i965 ice cover 4 is screwed into the partition opening and forms an extension of the sleeve. The lower end of the sleeve is permanently closed by a base 6 that is provided with an axial socket 7, the upper end of which is threaded and opens into the sleeve. Extending laterally through the base from the reduced lower end of the socket to the outside of the receptacle is an outlet passage 8 that is connected by a tube 9 to a suitable indicating instrument (not shown). The larger diameter part of the socket contains annular sealing means, preferably in the form of a pair of Teflon O-rings 12 separated by a spacing ring 13. These rings are held tightly in place by an annular nut 14 screwedinto the upper end of the socket.

Beside the receptacle there is an inlet tube 16 that is connected to a passage 17 that extends laterally into the receptacle base and then upwardly through its inner or upper face between socket 7 and the sidewall of the receptacle. An annular sealing gasket 18 engages the face of the base around the socket. Preferably the gasket is seated in a recess 19 formed in the base, so that the central portion of the base extends up into the gasket. The gasket is provided with an opening 21 registering with the inner end of the inlet passage 17 below it.

Removably disposed inside receptacle R is a canister C containing a gas-drying chemical. Any well-known material can be used for this purpose, such as silica gel and activated alumina, or a molecular sieve. The canister is formed from two concentric cylinders 22 and 23, the outer one 22 of which has a cap 254 on its upper end. Secured to the lower end of the outer cylinder is a closure 26 that also supports the inner cylinder 23. The closure is provided with a central opening 27 and with an ottcenter inlet hole 28 between the two cylinders. Extending through central opening 27 into the receptacle and rigidly mounted therein is a short, straight, axial nipple 29, the upper end of which opens into the inner cylinder. The rest of the nipple extends down into socket 7 and through sealing rings 12, by which it is tightly engaged. Its lower end is spaced from the bottom of the socket.

The upper end of the inner cylinder has an opening therein connecting it with the inside of the outer cylinder. Most suitably, this opening 31 is formed by spacing the upper end of the inner cylinder from the cap 24 above it. The porous gas-drying material 32 that substantially fills the two cylinders is spaced a short distance from the lower end of the inner cylinder by a convex screen 33, and is spaced in similar manner from closure 26 by a conical annular screen disposed between the two cylinders.

The receptacle cover 4 is screwed down into tight en gagernent with the canister C to press its lower end tightly against the sealing gasket 18 below it. To connect inlet passage 17 with the canister, it is preferred to provide the upper surface of the gasket with an annular channel 35 so that entering gas can flow around the gasket and into the canister through its inlet hole 23, regardless of the position of the hole relative to opening 20 through the gasket. The seal formed between the canister and gasket confines the gas to the proper passage.

With the canister in place, gas entering through tube 16 and inlet passage 17 flows up through the canister in the space between its two cylinder and then down through the inner cylinder and out through the nipple 29 and outlet passage 8. It will be seen that with this arrangement a spent canister can be quickly removed from the receptacle by unscrewing the cover and lifting out the canister. When a fresh canister is inserted, the nipple 29 is pushed down through the sealing rings in the base socket 7.

It is another feature of this invention that the state of the gas-drying material in the canister can be observed while in use so that the canister can be replaced before the material is completely spent. For this purpose, canister cap 24 is provided with a central transparent window 36, and the upper end of the canister is filled with a porous colorimetric material 37 that will change color when it absorbs a suificient amount of moisture from the gas flowing through the canister. By filling the space in the canister between the upper end of the inner cylinder and the window with such colorchange material, all of the gas flowing through the canister must pass through that material. Material suitable for this purpose is well known; it includes such chemicals as cobalt chloride and cobalt bromide, with which pads of paper or the like may be impregnated or coated. As the moisture content of the drying material 32 increases and it approaches the point where it will no longer function, the other material 37 becomes so moist that its color changes. The change can be observed through an opening 38 in case 1 and an opening 39 in the receptacle cover directly above window 36, whereupon the canister should be changed. However, if the color change is not noticed at once, there will be no immediate danger because there is suflicient drying material in the inner cylinder 23 to dry the gas for a further short period of time. For example, the canister may be designed so that the color change will take place after about eight hours of use, but with enough reserve capacity in the inner cylinder for it to function satisfactorily for another half hour.

It will be seen that both the inlet and the outlet of the canister are at one end of it, and that the color indicator is at the opposite end.. When receptacle cover 4 is screwed into place, it forces the canister into tight engagement with sealing gasket 18. When the cover is removed, enough of the canister is exposed to permit it to be gripped in the hand and pulled out of the receptacle. The cover is the only thing that has to be unscrewed to permit the canister to be separated from the receptacle.

According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

1. Gas-drying apparatus comprising a tubular receptacle having a base at one end and a removable cover at the opposite end, said base being provided with an axial socket that opens into thereceptacle and with an outlet passage connecting the outer end of the socket with the outside of the base, said base also having an inlet passage connecting the outside of the base with the inside of the receptacle beside the socket, a canister removably disposed in said receptacle and formed from concentric inner and outer cylinders having first and second ends, a cap on the first end of the outer cylinder adjacent said cover, a closure for the second end of the outer cylinder provided with a central opening and with an inlet hole between the cylinders, a nipple mounted in said opening and connected at one end with the second end of the inner cylinder, the opposite end of the nipple extending into said socket and communicating with said outlet pas- :sage, the first end of the inner cylinder having an opening therein connecting it with the inside of the outer cylinder, gas-drying material in said cylinders, an annular sealing gasket between said closure and base in engagement therewith and provided with a passage connecting said inlet passage and inlet hole, and an annular sealing means mounted in said socket and encircling said nipple in frictional engagement therewith, whereby gas Lentering through said inlet passage will flow lengthwise through both cylinders of the canister in succession and leave through said nipple and outlet passage.

2. Gas-drying apparatus as recited in claim 1, in which said receptacle cover tightly engages said canister cap to compress said gasket between the canister closure and receptacle base.

3. Gas-drying apparatus as recited in claim 1, including in the canister adjoining its said cap a material that changes color when it absorbs a sutficient amount of moisture, and a window in said cap, said receptacle cover being provided with an opening to permit said colorchange material to be viewed through the window.

4. Gas-drying apparatus according to claim 3, in which said first end of the inner cylinder is open and spaced from said window, and said color-change material fills the space between the window and inner cylinder.

5. Gas-drying apparatus comprising a tubular receptacle having a base at one end and a removable cover at the opposite end, said base being provided with an axial socket that'opens into the receptacle and with an outlet passage connecting the outer end of the socket with the outside of the base, said base also having an inlet passage ccnnecting'its outside with the inside of the receptacle beside the socket, an annular sealing gasket engaging the inner face of said base around the socket and provided with an opening registering with the adjacent end of said inlet passage, the side of the gasket opposite said base having an annular channel therein, a canister removably disposed in said receptacle and formed from concentric inner and outer cylinders having first and second ends, a cap on the first end of the outer cylinder adjacent said cover, a closure for the second end of the outer cylinder engaging said gasket, said closure being provided with a central opening and with an inlet hole connecting said gasket channel with the inside of the canister between the cylinders, a nipple mounted in said closure opening and connected at one end with the second end of the inner cylinder, the opposite end of the nipple extending into said socket and communicating with said outlet passage, the first end of the inner cylinder having an opening therein connecting it with the inside of the outer cylinder, gas-drying material in said cylinders, and annular sealing means mounted in said socket and encircling said nipple in frictional engagement therewith, whereby gas entering through said inlet passage will flow lengthwise through both cylinders of the canister in succession and leave through said nipple and outlet passage.

6. A gas-drying canister comprising concentric inner and outer cylinders having first and second ends, a cap on the first end of the outer cylinder and having an opening therein, a window in said opening, a closure for the second end of the outer cylinder provided with a central opening and with an inlet hole between the cylinders, a nipple mounted in said closure opening and connected at one end with the second end of the inner cylinder, the opposite end of the nipple extending axially away from the closure, the first end of the inner cylinder having an opening therein forming a passage between it and the inside of the outer cylinder, gas-drying material in said cylinders, and color-change material in the canister adjoining said window and disposed between said inner cylinder opening and the gas-drying material in the outer cylinder, said color-change material being adapted to change color when it absorbs a predetermined quantity of moisture.

7. Gas-drying apparatus comprising a tubular receptacle having a base at one end and a removable cover of the receptacle beside the socket, a canister removably disposed in said receptacle and formed from concen tric inner and outer cylinders said cylinders having first and second ends, a cap on the first end of the outer cylinder adjacent said cover, a closure for the second end of the outer cylinder provided with a central opening and with an inlet hole between the cylinders, the first end of the inner cylinder having an opening therein forming a passage between it and the inside of the outer cylinder, gas-drying material in said cylinders, and an annular sealing gasket between said closure and base in engagement therewith and provided with a passage connecting said inlet passage and inlet hole, the portion of said gasket around said gasket passage engaging said closure and base to separate the gasket passage from said central opening and socket, whereby gas entering through said inlet passage Will flow lengthwise through both cylinders of the canister in succession and leave through said central opening and outlet passage.

References Cited by the Examiner UNITED STATES PATENTS 9/32 Gardner et a1. 210-168 X 2/33 Bramsen et a1. 55322 12/52 Urdahl 55-387 11/61 Gibson 55-387 4/62 Robbins 55-389 X FOREIGN PATENTS 2/13 Germany.

HARRY B. THORNTON, Primary Examiner.

15 EUGENE F. BLANCHARD, Examiner. 

1. GAS-DRYING APPARATUS COMPRISING A TUBULAR RECEPTACLE HAVING A BASE AT ONE END AND A REMOVABLE COVER AT THE OPPOSITE END, SAID BASE BEING PROVIDED WITH AN AXIAL SOCKET THAT OPENS INTO THE RECEPTACLE AND WITH AN OUTLET PASSAGE CONNECTING THE OUTER END OF THE SOCKET WITH THE OUTSIDE OF THE BASE, SAID BASE ALSO HAVING AN INLET PASSAGE CONNECTING THE OUTSIDE OF THE BASE WITH THE INSIDE OF THE RECEPTACLE BESIDE THE SOCKET, A CANISTER REMOVABLY DISPOSED IN SAID RECEPTACLE AND FORMED FROM CONCENTRIC INNER AND OUTER CYLINDERS HAVING FIRST AND SECOND ENDS, A CAP ON THE FIRST END OF THE OUTER CYLINDER ADJACENT SAID COVER, A CLOSURE FOR THE SECOND END OF THE OUTER CYLINDER PROVIDED WITH A CENTRAL OPENING AND WITH AN INLET HOLE BETWEEN THE CYLINDERS, A NIPPLE MOUNTED IN SAID OPENING AND CONNECTED AT ONE END WITH THE SECOND END OF THE INNER CYLINDER, THE OPPOSITE END OF THE NIPPLE EXTENDING INTO SAID SOCKET AND COMMUNICATING WITH SAID OUTLET PASSAGE, THE FIRST END OF THE INNER CYLINDER HAVING AN OPENING THEREIN CONNECTING IT WITH THE INSIDE OF THE OUTER CYLINDER, GAS-DRYING MATERIAL IN SAID CYLINDERS, AN ANNULAR SEALING GASKET BETWEEN SAID CLOSURE AND BASE IN ENGAGEMENT THEREWITH AND PROVIDED WITH A PASSAGE CONNECTING SAID INLET PASSAGE AND INLET HOLE, AND AN ANNULAR SEALING MEANS MOUNTED IN SAID SOCKET AND ENCIRCLING SAID NIPPLE IN FRICTIONAL ENGAGEMENT THEREWITH, WHEREBY GAS ENTERING THROUGH SAID INLET PASSAGE WILL FLOW LENGTHWISE THROUGH BOTH CYLINDERS OF THE CANISTER IN SUCCESSION AND LEAVE THROUGH SAID NIPPLE AND OUTLET PASSAGE. 